Electrical control system



Z50-201 AU 252 EX 1m 31, 1933. J. H. HAMMOND, JR 9 ELECTRICAL CONTROL SYSTEM Original Filed lay 23, 1929 lnv entor-z John H. Hammond Jr; y His Attornes.

Patented Jan. 31, 1933 um'rsn's'rA'rss PATENT- osmos- Joan mars salmon, .13., or enoucasrxa, msacsosms. assmnon re sauna. nae-mic comm. acoaroaanou or saw you nun-loan co'n'rnon srs'rml on im's uuuu mu m as, me, lerlal Io. seam. Divided and um application ma an so,

mo. .larlal Io. 450.001.

My invention relates to electrical control systems, more particularly to electrical con trol systems for rotating members and has for an object the provision of improved means for controlling the relative speed of said members.

Although my invenion is not limited thereto, it has particular application in connection with synchronizing systems for a pair of rotating members which are located adjacent each other.

In accordance with my invention, I provide speed regieilat' means for one of the rotating mem rs an control the speed regulating means so that a synchronous speed condition will be maintained between the members. I conveniently control the speed regulating means bymeans of a suitable light-sensitive device, which is activated responsively to the movements of the rotating members.

This application is a division of my finding application, Serial No. 365,425, filedor a more complete understanding of my invention, reference should be had to the ac, companying drawing in which Fig. 1 is 9. diagrammatic view of a synchronizing system embodying my invention; Fi 2 is an elevation ta en on the line 2-2 c Fig. 1; F'

1 3 is an elevation taken on the line 3-3 of Ffig.

1; and Fig. 4 is a diagrammatic view 0 a modified form of my invention.

Referring to the drawing, I have shown my invention in one form in connection with a pair of rotatable shafts located adjacent each other. As shown, a shaft 10, mounted in a supporting bearing 11, is itioned adactuated in any suitable manner, while the rotatable shaft 12 will be actuated by means of an electric motor 13 which is shown to be lacent a shaft 12. The rotatab e shaft will I In order to cause the shafts 10 and 12 to rotate in synchromsm, I control the of the motor 13 responsivel to the motion of the shafts. To this end, provide suitable ected mechanically with the speedregulating means for the motor which will be controlled responsively to the motion of the shafts by means of a suitable li ht responsive means. As shown, this lig t res onsive control means comprises a sector s a d hous' or sup orting member 14 rigidly mounte on the s aft 10. This member is provided with a compartment 14a having two substantiall concentric curved openings 15 and 16. he opening 15 is provided with a transparent cover such as a plain sheet of glass, while the openin 16 is rovided with a covering or screen of mg opacity. Thus, the opening 16' may provided with a sheet of glass or other suitable material, that is' transparent at one end, shown as the right-hand end as viewed in Fig. 3, and o aqne at the other end, i. e., the left-hand en as viewed in Fig. 3. The portion between these: two ends is graded so that the opacity varies in a substantially uniform manner from the transparent end to the opaque end. Mounted within the compartment 14a and back of the opening 15 is a curved mirror 17 positioned substantially at an angle of to the' opening, and mounted within the chamber 140 op osite to the opening 16 is a second curve mirror 18 positioned substantially at an angle of 90 to the mirror 17.

A second supporting member 21, which is rovided with two compartments 22 and 23, is rigidly secured to the end of the shaft 12 adi'acent the sup orting member 14. A suitab e source of 1 umination 24, shown as an incandescent lamp, is suitably mounted within the compartment 22, and suitable light sensitive means 25, shown as a photo-electric cell, is mounted within the compartment 23. These compartments are rovided with apertures 26 and 27 (Fig. 2) tly opposite the openings 15 and 16, respectively, provided in the supporting member 14, and in these apertures are mounted suitable lenses 26a and 27a, respectively.

Mounted on the shaft 12 is a cylindrical insulating member 31, upon which is mountspeed ed three slip rings 32, 33 and 34, and

a mented commutator 35. Four brushes 363%, 38 and 89 are provided for engaging the three TAT;-

slip rings and the commutator, respectively. These brushes are mounted upon an insulated sulpport 40. As shown, the photo-electric ce is electrically connected to the two slip rings 32 and 33, while the source of illumination 24 is electrically connected to the slip ring 34 and to the commutator 35. The brushes 36 and 37 are electrically connected by two conductors 41 and 42 respectively, to an amplifier 43, which is tuned to the same frequency as produced by the commutator 35, which, for example, may by 500 cycles. It will be understood that the amplifier 43 will be of any suitable well-known construction. Thus for example, it may com rise suitable amplifying units of the thermionic character such as disclosed in my above mentioned copending application. It is believed unnecessary for a pro er understanding of this invention to descri in detail the form and construction of this amplifier.

The output of the amplifier 43 is electrical- 1y connected to the prlmary windin of a sired amount 69. This transformer 44. One side of the secon ary of this transformer is electrically connected by means of a conductor 45 to the grid of a tube 47, while the other side of this secondary is electrically connected by means of a con uctor 46 to one side of a battery 48. As shown, the other side of the batter 48 is electrically connected to the filament o the tube 47 and to one side of a battery 51, the other side of which is electrically connected to the other side of the filament, and by means of a conductor 52 to one side of the winding of a solenoid 53. The plate of the tube 47 is connected by means of a conductor 54 to one side of a battery 55, the other side of this bat-v tery being connected by means of a conductor 56 to the other side of the solenoid winding. A capacity 57 and an inductance 58 are connected electrically between the conductors 52 and 54.

As shown, one end of the solenoid core 61, i. e., the upper end of the core, is mechanicalliconnected to one end of a tension spring 62, t e other end of which is mechanic y connected, preferably by a swivel joint, to a thumb screw 63. This thumb screw is threaded into a suitable supporting bracket 64. It will be observed that the tension of the spring 62 may be adiusted conveniently to any dey turning the thumb screw 63. Mounted on but insulated from the core 61, is a suitable brush 65 which is provided to control a suitable adjustable resistance 66. This brush is connected by a flexible conductor 67 to a second adjustable resistance 68, which is provided with an adjustable brush rush, as shown, is electrically connected by means of a flexible conductor 71 to "one side of a battery 72. The other side of n this battery isconnected to the brush 39 ,through a switch 73 and a conductor74. The 65 conductor is electrically connected by means of a conductor 75 to one of the armature terminals 13a, the other armature terminal being electrically connected to the adjustable resistance 66 by means of a conductor 78. The conductor 74 is also connected to one of the field terminals 13?) by means of a conductor 81, the other field terminal bein electrically connected by means of the con uctor 84 to a suitable adjustable resistance 85. As shown, the resistance 85 is provided with an adjustable brush 86, this brush being electrically connected by means of the conductor 87 and the conductor 71 with the brush 69. The brush 86 is also connected by means of the conductor 88 with the slip ring brush 38. It will be observed that by reason of the above-described connections the battery 72 serves to electrically supply both the field and armature members provided for the motor 13, and also the incandescent lamp 24, which, as has been pointed out, is connected with the ring 34 and the commutator 35. It will also be observed that the field and armature members can be controlled by means of the adjustable resistances 68 and 85, and that the armature member is controlled automatically by means of the adjustable resistance 66. p

In the operation of this form of my invention, the shaft 10 is rotated in any suitable manner at a predetermined s' eed and the motor 13 is operated to brin t e shaft 12 up to this speed by adjusting the resistances 68 and 85 in the armature and field circuits, respectively. The switch 73, of course, will have been moved to its closed position so as to connect the battery 72 with the field and armature members.

. It will be understood that a pulsating current will be sent through the lamp 24 by reason of the commutator 35 intermittently breaking the circuit from the brush 39. P111- sating l1 ht rays, therefore, will be passed through t e lens 2611, through the transparent glass covering in the opening 15 and then will be deflected from the mirror 17 to the mirror 18, from whence the rays will be passed through the shaded glass in the 0 enm 16 and thence through the lens 27a. w ich focus the rays on the photoelectric cell 25. The current from the photo-electric cell will pass from the slip rings 32 and 33 through the brushes 36 and 37 from which it will be transmitted to the amplifier 43 by means of the conductors 41 and 42. It will be understood, therefore, that this current will be amplified, and that the amplified current will be transmitted to the power tube 47, which so plies current to the solenoid 53. It also Wlll be understood that this current will be proportional to the intensity of the light transmitted to the photo-electric cell 25..

ing member 14 as shown in Fig. 1. Under will be adjusted by means of the thumb screw 63 so that the brush 65 will be approximately solenoid will efiecta decrease in resistance 66 connected in the motor armacrease in th on the center of the resistance 66. With the var ous parts of the system in their res ctive positions just described, and shown in ig. 1, it will be understood that if the shaft 12 should lag behind the shaft 10, the supportmg member 21 will be moved relative to the supportin member 14 so that the photoelectric cel will be moved to a position opposite a less 0 aque part of the glass covering, provided or the o ening 16, and as a resu t a greater amount 0 mitted to the photo-electric cell. a greater amount of current will be caused to flow through the solenoid 53. This will cause the core 61 to be moved downwardly, as viewed in Fi 1, against the tension of the spring 62 a istance proportional to the increase of illumination upon the photoelectric cell. As shown, this op Obviously,

eration of the the effective ture circuit, and thereby will effect an ine motor armature current. The ipeed of the motor will be increased, thereore, until the supporting member 21 is brought back to its position opposite the center of the supporting member 14. When the supporting member 21 has thus been restored to its original position, the light transmitted to the photo-electric cell 25 will be reduced to its original intensity and as a result the current supplied to the solenoid 53 likewise will be-reduced to its original value.

' It will be obvious, therefore, that the core ture of 61 will move the brush 65 so as be-pos1- tioned over the center of the resistance 66. If the shaft 12 should overrun the shaft 10, the supporting member 21 will take up a position such that the photo-electric cell 25 will be 0 posite a denser or more opalll e portion 0 the glass inthe opening 16. T is movement of the shaft 12 therefore, cause the light received by the hoto-electric cell to be reduced and as a teen t the current supplied to the solenoid 53 will be reduced. It will be understood, therefore, that the spring 62 will pull the core 61 upwardly, as viewed in Fig. 1, so as to efi'ect an Increase in the resistance 66, which increase in resistance, of course, will effect a decrease in the motor speed so as to bring the shaft 12 back into synchronism with the shaft 10.

In the modified form of my invention shown in Fig. 4, I have dispensed with the solenoid 53 of Fig. 1. Otherwise, the structhe modification issubstahtially the the form shown in Figs. 1, in the modified form of the the shafts 110 and 112,

same as that of invention (Fig. 4)

' the motor 113 and the light responsive means i 65 corresponding parts will be identical in construction with the CROSS REFERENCE light will be trans-- will,

of the modification shown in Figs. 1, 2 and a. The housing 114.

mounted within the housing121 is electrically connected to the slip rings 132 and 133,

while the source of illumination, also mounted in the housing 121, is connected to the slip rin -134 and to the commutator 135.

he brushes 136 and 137, provided for the slip rings 132 and 133 respectively are connected by two conductors 141 and 142 to an amplifier 143 similar in construction to the amplifier 43 of Fig. 1. This angglifier is tuned to the same frequency as p'r uced by the commutator 135, ch, for example, may be 500 cycles.

The amplifier 143 is electrically connected with a power tube 147 as is the amplifier 43 of Fig. 1 connected with its tube 47. The output of the tube I47, however, is not connected to a solenoid, as is the amplifier 47, but is connected to control the motor field winding directly. As shown, the tube 147 is connected to the field terminals 113?) by means of conductors 192 and 193. A battery 194, preferably of comparatively high volta is connected in the conductor 193 andt ereb serves to electrically su ply the motor fiel winding. It will be un erstood, of course, that the motor 113 will be provided with a-field winding suitably wound to accommodate this high voltage. One of the armature terminals 113a, i. e., the lower terminal, as viewed in Fig. 4, is connected by means of a conductor 195 to an adjustable brush 196,.which is provided for the adjustable resistance197. .This resistance is electrically connected by means of a conductor 198 to a battery 199, the other side of which may be connected with mature terminal by means of aswitch 200 and a conductor 201. It will be understood nect the switch side of the battery with the brush 139 provided for the commutator 135;

and that the otherside of the battery is connected through a conductor. 202 with the brush 138 provided for the slip: ring .134.

This connection arrangement serves-to electrically interconnect the battery-199 and the source of illumination mounted in the support 21, since this source, as has been pointed and the commutator 135 are formed and of which can be adjusted by means of the-brush 196. It will be observed I that the conductor 261 also serves to con- EXAMINER the upper ar-' out, is electrically connected with the ring 134 and the commutator 135.

In this modified form of the invention it will be understood that the shaded glass in the opening of the supporting member 114 will be reversed so that the trans arent portion is toward the left, as viewe in Fig. 3, while the opaque portion will be toward the right as viewed in this figure.

In the operation of this modified form of the invention, if the shaft 112 lags behind the shaft 110, less light will be received by the photo-electric cell, which as has already been described will cause a decrease of the current controlled by the plate of the tube 147. As a result of this action, it will be obvious that the current supplied to the motor field will be decreased. This, as is well understood, will cause the motor to speed up so as to again bring the two shafts into synchronism. If the shaft 112 should run faster than the shaft 110, more light will be received by the photo-electric cell whereby the current in the motor field circuit will be increased. This increase of the field current will cause the motor to slow down until the shafts are again brought into synchronism.

It will be obvious that with either modification, disclosed in Figs. 1, 2 and 3, or in Fig. 4, the rate of restoration of the shafts to synchronism will be pro ortional to the magnitude of the angular isplacement between the shafts.

While I have shown several embodiments of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination with a plurality of rotatable members of means for maintaining a predetermined speed ratio between said members comprising light sensitive means, means for moving said light sensitive means in accordance with the speed of one of said members, a source of light for activating said light sensitive means, means for moving said source of light in accordance with the speed of one of said members, means for varying the intensity of l ght transmitted from said source to said light sensitive means in accordance with a departure in the relative speed of said members from said predetermined speed ratio and means controlled responsively to the intensity of light transmitted to said light sens?- tive means controlling the speed of one of said members so as to restore said predetermined ratio at a rate substantially. proportional to the magnitude of said departure.

2. The combination with a plurality of rotatable members of means for maintaining members, means said rotatable members in synchronism comprising light res onsive means, means controlled by said lig t responsive means for controlling the speed of one of said members, means for driving said light responsive means with one of said members, a source of light for actuating said light responsive means, a screen of varying opacity interposed between said light responsive means and its source of light and means for driving said screen with the other of said members so as to vary the light intensity transmitted to said light responsive means in response to a departure of said members from synchronism so that said members are restored to synchronism at a rate substantially proportional to the magnitude of the angular displacement between them.

3. The combination with a pair of rotatable members of means for maintaining said rotatable members in synchronism comprising light sensitive means connected to be moved in synchronism with one of said rotatable members, a source of light for activating said light sensitive means connected to be moved in synchronism with one of said rotatable for varying the light intensity transmitted to said light sensitive means in response to a departure of said members from synchronism and speed controlling means for one of said members controlled by said light sensitive means. 4. The combination with a plurality of rotatable members of means for maintaining the members in synchronism comprising means for'regulating the speed of one of said members, a photo-electric cell connected to control said speed regulating means, means for driving said photo-electric cell with one of said members, a source of light for activating said photo-electric cell, means for driving said source of light with said one member, a screen of substantially uniformly varying opacity interposed between said photo-electric cell and said source of light, means for driving said screen with the other of said members so as to control the intensity of light transmitted from said light sourceto said photoelectric cell whcreby when said members depart from synchronism said speed regulating means is controlled to efiect the restoration of said members to synchronism at a rate substantially proportional to the magnitude of said departure.

5. The combination with a plurality of rotatable members of means for maintaining said rotatable members in synchronism comprising light-sensitive means, a source of light for activating said light-sensitive means, a screen of substantially uniformly varying opacity interposed between said light-sensitive means and its source of light, means for moving said light sensitive means and said source of light in acco dance with the rotation of one of said members and said screen able members in synchronism comprising a photo-electric cell mounted upon the first of sou'rceof li ht to said light-sensitive means gul said members, a source of light for activating said photo-electric cell mounted upon said first member, means mounted upon the second of said members for directing the light rays from said light source to said photoelectric cell, means positioned in the path of said rays for varying the light intensity transmitted to said p oto-electric cell in response to a departure of said members from chronism and means controlled by said of one of said members.

7. The combination with a plurality of mtatable members of means for maintaining said members in synchronism com rising speed rcgplating means for one of sai members, lig t-sensitive means for controlling said speed regulating means, means for movmg said light sensitive means in accordance with the rotation of one of said members, a source of light for activati said 1' ht-sensitive means, a screen of en antia y uniformly varying opacity for controlling the intensity of hght transmitted from said and means or moving and screen in accordance with the rotation of the other of said members so that the intensity of light transmitted to activate said light-sensitive means is varied in accordance with. a departure of said members from synchronism.

8. The combination with a pair of rotatable members of means for maintaining said memhere in synchronism com risin d re lating means for one'of s did m mm lig tsensitive means controlling said speed regulatin means driven at a speed bearing a substantially'constant ratio with the speed of one of .said mcmbers,;a source of light for activating said light-sensitive means driven at a speed bearing a substantiall constant ratio with the speed of one of sai members, a screen of substantially uniformly varyin opacity arranged to control the intensity 0 hght transmitted from said source of light to said light-sensitive means and means controlling said screen to vary the intensity of light transmitted to activate said light-sensitive means in accordance with a departure of said members from synchronism so that said members are restored to synchronism at a rate substantially proportional to the magnitude of said departure. Y r

9. The combination with a pair of rotatable members of meansfor maintaining said rotatable members in synchronism comprisiag light-sensitive means driven at a speed CROSS REFERENCE driven at a spec responsive means for controlling the speed bearing a substantially constant ratio-with the speed of one of said members, a source of light for activatin said light-sensitive means bearing a substantially constant ratio with the speed of said one member, a screen of varying o acity arranged in the ath of the light rays om said source of lig t to said light-sensitive means and driven at a speed bearing a substantially constant ratio wlth the speed of the other of said members so as to control the light intensity transmitted to the light sensitive means in response to a departure of said members from chronism' and means controlled by said hght-sensitive means for controlling the speed of one of said members. 10. The combination with a plurality of rotatable members of means for maintaining said members in synchronism comprisin means for regulating the speed of one of sai members, light sensitive means controlling said speed regulatin means, a source of light for activating said light sensitive means, means for moving said light-sensitive means and said source of light in accordance with the rotation of one of said members, a screen arranged in the path of the rays of light from said source of ight to said light-sensitive means, said screen varying substantially uniformly inopacity from one portion thereof to another portion thereof, an intermediate section corresponding to the osition of anar a cement between sai members and means or moving said screen in accordance lwith the rotation of the other of said memrs. i 11. The combination with a pair of rotat- I able members ofmeans for maintaining said EXNMNER of said members for directin the light rays from said light source to sai light-sensitive means and a screen of substantially uniformly varying opacity on said other member pos1 tioncd 1n the path of said rays so as to vary the light intensity transmitted to said lightsensitive means in accordance with a departture of said members from synchronism. v

12. The combinationwith a pair of rotatable members of means for maintaining said rotatable members in synchronism comprismg a motor for operating one of said memhers, light-sensitive means connected to be moved at a speed bearing a substantially constant ratio with the speed of one of said members, a source of light for activating said light-sensitive means'connected to be moved at a speed bearing a substantiall constant ratio with the speed of one of sai members,

my hand means for va ing the light intensity transmitted to sai light-sensitive means in response to a departure of said members for nchronism and means responsive to said light sensitive means for controlling the speed of said motor.

13. The combination with a pair of rotatable members of means for maintaining said rotatable members in synchronism comprising a motor arranged to operate one of'said members, a controlling resistance for said motor, a light sensitive cell arranged to be rotated at a speed bearing a substantially constant ratio with the speed of rotation of said one member, a source of light for activating said light-sensitive cell arranged to be rotated at a speed bearing a substantially constant ratio with the speed of said one member, means for varying the light intensity transmitted to said light sensitive cell in response to a departure of said members from s chronism and means responsive to the actlvation of said light sensitive cell for controlling said speed controlling resistance.

In witness whereof, I have hereunto set this 20th day of May, 1930. JOHN HAYS HAMJHOND, JR. 

